GB2588404A

GB2588404A - Valve Washer

Info

Publication number: GB2588404A
Application number: GB1915243.8A
Authority: GB
Inventors: Sach Martin
Original assignee: Nexgen Plumbing Products Ltd
Current assignee: Nexgen Plumbing Products Ltd
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2021-04-28
Anticipated expiration: 2039-10-22
Also published as: GB201915243D0; GB2588404B

Abstract

A washer 200 for sealing a valve 100 such as a water plumbing valve has a tapered front surface for engaging with a seat 130 of the valve 100 to seal it and a hole in a flat rear surface for connecting to a stem 110 of the valve. The hole includes a plurality of clips (280, Fig. 6) to engage with a projection on the stem 110 to provide a tight grip. The washer 200 is made from a hard plastics material and can be used as a replacement for typical flat-disc rubber washers.

Description

VALVE WASHER

BACKGROUND OF THE INVENTION

[0001] The present invention relates to washers for creating a seal in a valve, particularly for use in domestic 5 and commercial plumbing systems.

[0002] Many different water and other fluid valves use a disc-shaped, rubber washer that is attached to a stem via a central hole. A typical drain valve 100 having a stem 110 and flat rubber washer 120 is illustrated in Figure 1. The stem 110 is screwed into the valve 100 to press the washer 120 flat against a flanged seat 130, blocking an outlet 140 in the valve 100 and preventing the flow of water or other liquid. Flow is permitted by unscrewing the stem 110 so that the washer 120 moves away from the seat 130.

[0003] There are many disadvantages with rubber washers.

Over time, the rubber of the washer can degrade in many different ways, compromising the seal between the washer and the seat. For example, the face of the rubber washer can fuse with the seat of the valve. When the stem is later unscrewed, the washer separates from the stem and remains stuck inside the valve body. Rubber can be compressed too much by overtightening of the stem, resulting in a leaking valve. Severe over-compression of the washer can cause inelastic deformation, so the washer stays compressed even when not under load. The rubber can suffer chemical fatigue and become hard and brittle, especially when subjected to alternating hot and cold or to chemicals/minerals in water. Even when new, the size tolerances in both washer and stem manufacture are quite loose so washers may not always fit onto the stem or may not fit securely.

[0004] G32537611 tackles some of these disadvantages and describes a single-piece, screw-threaded insert for a drain valve, illustrated in Figure 2. The insert 150 is integrally formed from a plastics material that does not degrade over time, like typical rubber washers, or rust, like the metal components of typical stems.

[0005] Additionally, the front end of the insert 150 of GB2537611 is tapered so that and squared off edge on the flange of the drain valve seat 130 engages with the tapered 10 front end of the insert 150. This provides an improved fluid-tight seal between the insert 150 and the seat 130.

[0006] In order to operate the insert of GB2537611, the rear of the insert is provided with an opening for receiving a hex key or screwdriver 160. Advantageously, the insert 150 can therefore be concealed within the drain valve 100 to prevent accidental opening. As a consequence, however, the insert of GB2537611 is only suitable for drain valves or other valves that are not regularly operated and is not useful for most plumbing applications such as in taps/faucets and spigots.

SUMMARY OF THE INVENTION

[0007] The present invention provides a washer for use in sealing a valve, the washer having a rear end and a front end, the rear end comprising a substantially flat rear surface and having a centrally located hole for connecting the washer to a valve stem, an interior of the hole comprising a plurality of clips, each clip having a lip oriented towards the centre of the hole, the front end comprising a sealing surface for engaging with a valve seat to seal the valve in use.

[0008] Washers embodying the present invention can replace common flat, disc-shaped washers and fit onto a valve steam via the hole in the rear surface in the same manner as flat washers. Providing clips within the hole means that the washer can fit onto a range of different sized stems and ensure a good grip on the stem even when manufacturing tolerances of the stem are loose.

[0009] The washer is also not limited to drain valves or any one specific type of valve but can be used with taps, faucets, spigots and other domestic and commercial water plumbing valves, and even with valves for other purposes and other fluids.

[0010] Preferably, the sealing surface is a tapered sealing surface. Providing the front surface of the washer with a tapered profile, rather than simply presenting a flat surface to a valve seat, ensures a more effective seal with the valve seat that is less prone to sticking and fusing with the valve seat over time. In particular, the tapered surface only meets the valve seat at a circular edge rather than over a wide surface that is prone to sticking.

[0011] Preferably, the tapered sealing surface is a conical surface, and may be in the shape of a truncated cone with the tapering sides of the cone engaging with the valve seat in use. A conical sealing surface is a simple and effective shape for creating a water-tight seal with the valve seat when the valve is closed. The front face of the truncated cone, which does not engage with the seat in use, is preferably in the shape of a dome to avoid sharp edges.

[0012] Preferably, the washer is formed as a single piece of a hard and/or substantially rigid and/or substantially incompressible plastics material such as acetal plastic. Using a hard plastics material rather than soft rubber as in common flat washers means that the washer is more hard wearing and less prone to degradation over time. Using a substantially rigid plastics material means that the clips provide a more secure grip on the stem. Using a substantially incompressible plastics material avoids the problems with over-compression or permanent deformation of rubber washers that can compromise the seal. Advantageously, the washer can be moulded as a single piece of plastic.

[0013] Preferably, the washer includes a cylindrical portion between the substantially flat rear surface and the sealing surface. This cylindrical portion, which may be similar in size and shape to a typical flat washer, adds structural strength to the washer and fills the interior of the valve body to prevent fluid escaping along the valve body when the valve is opened.

[0014] The present invention also provides valve comprising a stem, a seat and a washer as described above removably connected to the stem, the stem being movable between a first position where the valve is open and a second position where the washer engages with the seat, sealing the valve.

[0015] Preferably, the sealing surface of the washer is tapered and engages with an edge of the seat to seal the valve when the stem is in the second position and further extends past the edge. By engaging with the edge of the seat and extending past it, the tapered sealing surface ensures a water-tight seal when the valve is closed with minimal contact between the washer and the seat.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Preferred embodiments of the invention will now be described with reference to the accompanying drawings in which: [0017] Figure 1 is a cut-away view of a known drain valve arrangement having a screw-threaded stem and a flat rubber washer; [0018] Figure 2 is a cut-away view of known drain valve arrangement having a screw-threaded, single-piece insert; [0019] Figure 3 is a cut-away view of a valve washer embodying the present invention positioned in a drain valve; [0020] Figure 4 is a perspective view of a sealing surface of a valve washer embodying the present invention; [0021] Figure 5 is a side view of a valve washer embodying the present invention; and [0022] Figure 6 is a perspective view of a rear surface valve washer embodying the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Figure 3 illustrates a washer 200 embodying the present invention in use within a drain valve 100. The possible use in a drain valve 100 is just one example for ease of illustration. In general, the washer 200 is extremely versatile and can be used in many different types of valve to replace a typical flat washer 120. Also, although the washer 200 in Figure 3 is attached to a stem 110 having a spanner adaptor 210 for operating the valve, the stem 110 may have or may be connected to any suitable actuation means such as a handle or an automated actuation device.

[0024] Washers 200 embodying the present invention are intended to replace conventional flat, rubber washers such as the flat washer 120 illustrated in Figure 1. Such washers have a centrally located circular hole passing completely through the flat washer 120 for connecting the flat washer to a stem having a corresponding cylindrical projection 220. The tip of the projection 220 overhangs the hole in the flat washer 120 to grip the flat washer 120 and hold it in place on the stem 110 when the valve 100 is opened and closed. The stem 110 and flat washer 120 illustrated in Figure 1 are ubiquitous in commercial and domestic water plumbing systems, though there are many different standard sizes for their outer diameters and for the diameters of the hole and/or cylindrical projection 220.

[0025] As will be described in more detail below, a washer embodying the present invention fits onto the projection on a stem 110 in a similar manner to the flat washer 120 so that it can immediately replace existing flat washers without the need for additional tools or modification/replacement of the stem 110 or valve 100. A washer 200 embodying the present invention will generally be thicker than a flat washer 120, so the closed position of the valve will be further back than normal, as can be seen by comparing Figure 1 with Figure 3, but this does not affect the operation of most valves.

[0026] As best illustrated in Figures 4 to 6, a washer 200 embodying the present invention has a front surface comprising a tapered, preferably conical sealing surface 230 for engaging with a seat 130 in order to seal a valve 100, and a flat rear surface 240 for abutting against flat front surface of a valve stem 110.

[0027] In cross-section through a plane parallel to the flat rear surface 240, the washer 200 has a circular outline. Advancing the cross-section from the rear surface 240 towards the front of the washer 200, the diameter of the circular outline remains constant for a cylindrical portion 250 of the washer 200 and then reduces to define the sealing surface 230. The cross-sectional di ameter preferably reduces linearly to define a conical sealing surface, but other tapering shapes are possible such as a spherical surface or any curving dome shape. The cross-sectional diameter optionally reduces consistently to a point, forming a complete cone or some other continuously smooth curved surface. Preferably, however, the sealing surface 230 is truncated leaving either a flat or slightly domed front face 260, or by providing some other discontinuity to steepen the curvature of the sealing surface 230 to form the front face 260.

[0028] In use, it is the sealing surface 230 of the washer that engages with the seat 130 of the valve 100, so the surface is truncated only once the cross-sectional diameter of the sealing surface 230 is less than the diameter of the aperture in the seat 130. The shape of the front face 260 therefore does not affect the sealing operation of the washer 200 and can be chosen to simplify manufacture, improve structural strength, or even for aesthetic reasons. In the Figures, for example, the sealing surface 230 of the washer 200 comprises a truncated, right circular cone and the front face 260 is formed as a smooth, low dome to avoid sharp edges which might weaken the structure of the washer 200.

[0029] Located centrally on the rear surface 240 is a hole 270 for receiving the projection 220 of the stem 110 to connect the washer 200 to the stem 110. The hole 270 does not pass all the way through the washer 200 but instead has a base 275 within the washer 200. The hole 270 may be circular in outline and has an internal circular lip for engaging with an overhang on the projection 220 in order to hold the washer 200 in place on the stem 110. Preferably, the hole 270 contains a plurality of clips 280 arranged in a circle which receive and grip the overhang on the projection 220. Each clip 280 comprises a post connected to the base 275 of the hole 270 and extending towards the rear surface 240, each post having a flange or lip oriented towards the centre of the hole 270. On inserting the projection 220 into the hole, each post flexes outwardly to permit entrance of the projection 220 and then snaps back when the overhang passes its lip to grip the overhang. In this way, the washer 200 can be used with stems 110 having a range of differently sized projections 220 and is not limited to being used with one single size as is the case with typical flat washers 120.

[0030] The washer 200 is preferably formed as a single piece from a substantially rigid, substantially incompressible, hard plastics material compared to the elastic, compressible, flexible, soft rubber as used in typical flat washers 120. Suitable plastics materials include polybutylene. A preferred plastics material is acetal plastic or polyoxymethylene which is resistant to degradation, relatively incompressible under the forces experienced in normal use as a washer 200, can be recycled, and will not stick or fuse with the seat 130 of the valve 100 over time.

[0031] The cylindrical portion 250 of the washer 200 preferably has a smooth, unthreaded surface. In use within a valve 100, the cylindrical portion 250 substantially fills the interior diameter of a valve 100, having substantially the same diameter as the screw threaded portion of the stem 110. When formed from a suitable plastics material, the threaded inner surface of the valve 100 presses or even cuts into the cylindrical portion 250 as the washer 200 is moved within the valve 100 by operation of the stem 110. In this way, the cylindrical portion 250 creates a fluid tight seal, preventing fluid from moving past the washer 200 along the interior of the valve 100, particularly when the valve is opened, so that the fluid instead only exits the valve through the outlet 140. Generally, abutment of the cylindrical portion 250 against the inner surface of the valve 100 improves the sealing property of the valve.

Claims

CLAIMS: 1. A washer for use in sealing a valve, the washer having a rear end and a front end, the rear end comprising a substantially flat rear surface and having a centrally located hole for connecting the washer to a valve stem, an interior of the hole comprising a plurality of clips, each clip having a lip oriented towards the centre of the hole, the front end comprising a sealing surface for engaging with a valve seat to seal the valve in use.
2. The washer of claim 1 wherein the plurality of clips are arranged in a circle, the lip of each clip oriented towards the centre of the circle.
3. The washer of claim 2 wherein each clip is arranged to flex away from the centre of the circle to permit a projection 15 having an overhang to pass inside the circle of clips and to clip over the overhang once the projection is inserted.
4. The washer of any preceding claim wherein the sealing surface is a tapered sealing surface.
5. The washer of claim 4 wherein the tapered sealing surface 20 is in the shape of a cone.
6. The washer of claim 5 wherein the cone is truncated, the tapering sides of the cone for engaging with the valve seat in use.
7. The washer of claim 6 wherein a front face of the 25 truncated cone is in the shape of a dome.
8. The washer of any preceding claim formed as a single piece.
9. The washer of any preceding claim formed from a substantially rigid, substantially incompressible plastics material.
10. The washer of claim 9 wherein the plastics material is 5 acetal plastic.
11. The washer of any preceding claim further comprising a cylindrical portion between the substantially flat rear surface and the sealing surface.
12. The washer of any preceding claim wherein a cr0ss10 sectional outline of the washer in a plane parallel with the flat read surface is circular.
13. A valve comprising a stem, a seat and a washer connectable to the stem, the stem being movable between a first position where the valve is open and a second position where the washer engages with the seat, sealing the valve, the washer comprising the washer of any preceding claim.
14. The valve of claim 13 wherein the sealing surface of the washer is a tapered sealing surface which engages with an edge of the seat to seal the valve when the stem is in the second 20 position and further extends past the edge.